Water pipeline for water backfeeding and irrigation

I don't have a flat tank. But I suspect that the bottom is not completely even. What kind of pump do you have now? Floating suction? You can also hang the pump on a rope/chain. This way it stays upright. Sucking directly at the bottom is not good anyway because you might pump sediments into your water cycle…

Yes, it is the DAB40/50 Pulsar Dry with floating suction. An employee from Graf said I have to operate it outside the tank. Of course, that is not possible. But if I hang the pump on a rope, that works, right?

Yes, it works without problems on the rope. It is a submersible pump. You can't set it up dry anyway.

Now I first have to clarify how I am supposed to get a submersible pump into the cistern anyway. The installation pot for the inlet is in the way and I also see no way to remove it once the KG pipes are connected.

Pot out, pump in, pot in. You can also just drill another hole in the pressure line.

Yes, that was the plan. So I will drill the pressure lines out of the dome to fit. But there are two lines connected to the red pot. How am I supposed to get the pot out if two lines are connected?